Method for determining the position and/or orientation of a creature relative to an environment

ABSTRACT

A method for determining the position and/or orientation of a creature ( 3 ) relative to an environment by connecting the creature ( 3 ) to a locating member ( 4 ) including a transducer ( 5 ) so that the relative positions and/or orientations of the creature ( 3 ) and the transducer ( 5 ) are arranged to be within a limited interval. The transducer determines its position and/or orientation relative to the environment by receiving incident signals from the signal sources ( 9 ) in the environment, and the position and/or orientation of the creature ( 3 ) is determined by the position and/or orientation determined for the transducer ( 5 ).

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This is a Continuation of International ApplicationPCT/SE02/00968 filed on 21 May 2002, which designated the United Statesof America.

FIELD OF THE INVENTION

[0002] The present invention relates to a method for determining theposition and/or orientation of a creature relative to an environment, amethod for locating a phenomenon in an environment, a method fordetermining if the position and/or orientation of a phenomenon relativeto an environment is in accordance with a reference, and a method fordetermining if the position and/or orientation of an object relative toan environment by means of a creature.

[0003] Such methods may be used for a number of purposes, buthereinafter the particular, but not in any way limiting for theinvention, fields of application constituting a means for guiding andsupervision of a creature, and for scanning, guarding or checking anobject, an area or a volume by means of a creature will be described.

[0004] Initially, a number of terms used in the present application willbe explained and defined more closely below. In this connection, it isemphasised that the terms “creature”, “object”, “phenomenon”,“environment”, “indoors”, “semi-indoors”, “model”, “position”,“orientation”, “authorization”, and “abstract stations” occurring in thetext are to be given very broad meanings in accordance with thefollowing definitions.

[0005] The term “creature” includes human beings and animals. Although,animals belonging to the group of mammal are intended in the firstplace, also other animals such as birds, fishes, batrachians andreptiles, and insects are included.

[0006] By the term “object” both physical things and creatures or partsthereof are intended.

[0007] In addition to creature and things the term “phenomenon”comprises also steam, liquids, shadows, lights, sources of a sound,waves, vibrations, motions, propagating cracks, draught, flows,vortexes, turbulence, discolorations and tints, and other comparablephenomena.

[0008] An “environment” may be constituted by one or more physicalthings or parts thereof, and/or creatures, as well as by an arbitraryvolume with or without physical limiting surfaces. The volume or thespace may include one or more solid objects and/or contain differentmediums in a gas state and/or a liquid state. It is also possible thatthere is vacuum in the volume. In the environment both stationary andmovable objects/phenomena may occur. The current environment may belocated both outdoors and indoors and possess a great or small extensioncompared to the creature.

[0009] The present invention is intended to by applied primarily“indoors” and “semi-indoors”. The term indoors includes all types oflocations inside different kind of permanent or temporary buildings andconstructions, or naturally occurring enclosings, such as dwellinghouses, factory premises, offices, tents, caves, tunnels, mines, butalso simpler constructions in which there are walls, pillars, and/ormasts which support some kind of roof. The roofs may cover the currentarea totally or be designed as a net, lattice or battens. Also placesinside different kind of crafts, such as vessels, trains, cars,aeroplanes and spacecrafts are counted among the category indoorenvironments. In the term semi-indoors places located outdoors in thevicinity of constructions or naturally occurring objects and close tothe outer limitations of the indoor environments, such as in thevicinity of roads, roofs, masts, pillars, power lines, towers, walls,lamp-posts, bridges, trees, rock formations, stones, bushes, longvalleys and hills, puddles, shorelines, variations in vegetation, etc.,are intended.

[0010] It should also be emphasised that the term “model” is intended tocomprise everything from very simple models of environments, such as fewco-ordinated data, graphs, drawings, maps, etc., to more advanced two-,three- or higher dimensional models, which may be moved, rotated,changed or processed in any other way, for example in a computer graphicenvironment for picture processing and/or evaluation, and also the mostadvanced models as regards interactive application, the so calledvirtual reality (VR) models, in which a user in a virtual way may takepart of the properties of an environment. Furthermore, the models mayinclude photographic still pictures and moving pictures in the form offilm sequences. In a model vectorial quantities, such as a gas flow, maybe illustrated by means of arrows in such a way that the direction andlength of an arrow denote the direction and the value, respectively ofthe present quantity. Furthermore, other quantities, which very oftenare non-anisotropic quantities, such as temperatures, radiationintensities, etc., may be illustrated in the form of differentlycoloured transparent surfaces representing surfaces in a volume alongwith surfaces a current quantity has for example a constant value. Inaddition, holographic reproductions and models of abstract andmathematical character are also included, such as those which depict anenvironment by means of for example reciprocal spaces.

[0011] Furthermore, the terms “position” and “orientation” have thefollowing meanings. A three-dimensional object, i.e. a physical articleor a creature, may have up to six spatial degrees of freedom, threetranslations and three rotations. The “position” of the object isdefined by the three quantities which denote translations in relation tothe origo of a current coordinate system. These are denoted in thisapplication by x, y and z. However, it is also possible to denote theposition parameters in other coordinate system, for example in polarcoordinates, (r, φ, φ). The “orientation” of the object is defined bythe three quantities which denote the angles of rotation of the objectin the coordinate system. These are denoted in this application by α, βand γ.

[0012] In practice, an object often has a number of degrees of freedomwhich is less than six. A cursor on a computer display, for instance,usually has two degrees of freedom. Its orientation is constant (orirrelevant), and its position is characterized by two variables.Similarly, a three-dimensional object may have such limitations that ithas fewer than six degrees of freedom. For example, a block movable on atable has three degrees of freedom—two variables indicates its positionon the table top and one variable its orientation, i.e. its angle ofrotation about an axis perpendicular to the table top.

[0013] “Authorization” means that a creature has admittance, or has notadmittance, to a certain area/volume in an environment or to an objector is permitted, or is not permitted, to perform a certain action. Forthis authorization it may also be special conditions to be fulfilled,such as a certain point of time or a predefined action which has to beperformed by the creature or by any other, or that a special state ispresent in the environment or that a certain occurrence has occurred oroccurs.

[0014] “Abstract stations” is selected sets of positions and/ororientations in the environments which not necessarily need to coincidewith the position or extension of a physical thing, but an abstractstation may be defined by one or more selected position- and/ororientation parameters depending on, or independent of, the propertiesof the environment, and possibly by a specific time interval.

[0015] Furthermore, it should be pointed out that although applicationexamples are initially described below in which the relative movementbetween the device used for accomplishing the methods, or at least partsof the device, and the environment, is performed by moving the deviceitself, it is in some cases possible to use a stationary device andinstead accomplish the relative movement by moving the environment, forexample in the cases in which the environment is constituted by anobject which is not stationary installed.

PRIOR ART

[0016] Within a number of different fields there is a need to locate aphenomenon in an environment or to locate a creature, often a humanbeing, or an object connected to the creature, as regards its positionand/or orientation relative to a previous position and/or orientation orrelative to an environment. The object may be for example a craft ofsome kind in which the creature is present or an object in theenvironment, the position and/or orientation of which is desired to becontrolled by means of the creature.

[0017] For example within the field of guarding, there is a need tocheck and/or supervise the movements of a guard and other possibleactions performed by the guard at moments when the guard patrols aso-called guard path, for example in a building. In accordance withprior art, this is performed by the fact that the guard is imposed toperform an action at certain predetermined locations (control stations)along the guard path, such as turning a key, with the use of shortdistance transponders or plates readable by remote sensing or mechanicalcontact, or performing a reading of a bar code, which confirms that thecurrent guard has been at the current place at a certain moment. This isused to obtain information about whether the guard has or has notexecuted his instructions during the current guard path. In addition, byocular inspection, the guard may establish to some extent if objects inthe environment are correctly positioned or if unauthorized persons arepresent in the building and if so is desired, he may transfer thisinformation to someone else, for example to a guard officer, the policeetc.

[0018] As a complement to the observations of the creature, manydifferent types of sensors may be used for indicating different statesin the environment. To indicate that a window has been crushed, aglass-crushing detector may be used and by means of an alarm devicearranged at the window, information may be obtained, for example aboutthat the window is open although it should be closed.

[0019] However, the procedure described above has several disadvantages.These are foremost associated with the lack of flexibility. The guardpath is determined beforehand with small possibilities of changing thepath when it has already begun. It is true that it is possible to varythe sequence of the control stations which are to be visited, but thenumber of different movement paths is still limited. Furthermore, thepossibility to supervise the guard is very restricted and, actually,only knowledge about if the actions mentioned above are performed or notand about in which order and/or at which points of time these actionspossibly have been performed, is obtained. However, any informationabout the path of movement of the guard or where the guard is presentbetween the control stations is not obtained other than indirectly inthe cases there is knowledge about by which speed the guard moves andabout the time difference between actions performed at different controlstations. In addition, many and stationary installations of controlstations are often needed to enable guard paths of the kind discussedherein and if objects in the environment are to be checked in anotherway than by the guards' observations, large installations of differentkinds of sensors and/or cameras throughout the environment are needed.In addition, there is no way besides the guards' observations to locatea phenomenon which occurs in an unexpected place, at which there is nosensor placed out. Such a phenomenon may be a machine breakdown, aleakage of a pipe, an object, etc., which is present/is not present. Itis true that there is a possibility to use sensors and/or cameras whichcover a relatively great area, but then such an indication is oftenassociated to a comparatively great inaccuracy as regards the positionof the phenomenon. For example, with a sensor located at the floor levelin a room, it may be determined if there is a leakage in a water pipeoccurring in the room, but it is not possible to determine where in theroom the pipe having a leakage is located or where on the pipe theleakage has arisen.

[0020] Another field related to the field of guarding is supervision ofpeople serving a sentence because they have committed a crime. In thisconnection, it may come into question to supervise a person who is inprison as well as a person who serves a sentence in another environmentin the community. It becomes more common, particularly as regardslighter offences, that a person who is found guilty of a crime undercertain given conditions is offered the alternative to serve thesentence in another environment, for example at home, different from theconventional prison environment. Usually, in such a case, certainrestrictions as regards the freedom of movement are imposed upon thepunished person, i.e. he/she has permission to be only within certaingiven areas during certain given time intervals. This means that inpractice, the person often must stay only in his/her own house.Exceptions may be made during a certain time, for example to enable theperson in question to perform work in another location. Furthermore, asa service in return, the person has to carry a so-called electronic tagwith the purpose of continuously determining the position of the person,so that it may be checked that the person does not exceed therestrictions which are present. According to already establishedtechnique, the supervision is performed by that the electronic tagattached to the person substantially continuously transmits signals to areceiver in the environment, so that any movements of the person may berecorded. A great disadvantage with this technique is that the signalstransmitted may be bugged also by non-authorized persons and be used fortracking the person who carries the tag. Thus, it is possible thatpeople who for example may constitute a safety threat against the personin question could obtain information about where the person is presentby intercepting the signals by means of a receiver.

[0021] A further field where a need to locate a phenomenon in anenvironment or locate a creature, often a human being, or an objectconnected to the creature, as regards its position and/or orientationrelative to a previous position and/or orientation or relative to anenvironment, is present in guidance and/or guiding people, for examplein connection with exhibitions, visits in shops, stores, shoppingcentres, museums and hospitals or at railway stations and air terminals,etc. The technique used nowadays is in most cases communication ofinformation to the current person via signs and displays located in theenvironment or via portable written information, such as maps and otherdocuments. However, in this case the possibility to give adequateinformation based on the position and/or orientation of the person, withthe purpose of guiding the person, is missing, with the exception ofparticular information stations, which have a map by which the personmay determine its approximate position relative to the environment andreceive information about for example the choice of way to be able tomove to a certain place in the best way. However, this procedure isstatic and does not offer the possibility to interact to the extentwhich often is desired to satisfy the desires of the person.

THE OBJECT OF THE INVENTION AND SUMMARY OF THE INVENTION

[0022] A first object of the present invention is to provide a methodfor determining the position and/or orientation of a creature relativeto an environment, which method may be applied both indoors andsemi-indoors, and without the creature having to seek up a certain placefor enabling the position- and/or orientation determination, and in away that the risk for non-authorized tracking of the creature issubstantially reduced.

[0023] This object is attained according to the invention by a methodfor determining the position and/or orientation of a creature relativeto the environment, comprising that the creature is connected to alocating member including a transducer, so that the relative positionsand/or orientations of the creature and the transducer are arranged tobe within a limited interval, the transducer determining its positionand/or orientation relative to the environment by receiving incidentsignals from signal sources in the environment, and that the positionand/or orientation of the creature is determined by means of theposition and/or orientation determined for the transducer. Such a methodmay be used in all environments where the required signal sources havebeen arranged or are present in the form of naturally occurring objects.Furthermore, the position- and/or orientation determination may beperformed for any position/orientation on condition that the transducerreceives the required signals from the signal sources. By the fact thatthe transducer determines its position and/or orientation by means ofsignals which incident on the transducer, the risk of non-authorizedtracking of the creature is minimized.

[0024] According to another preferred embodiment of the method accordingto the invention for determining the position and/or orientation of acreature relative to an environment, the position and/or orientation ofthe creature is repeatedly determined when the creature moves, by thatthe transducer repeatedly determines its position and/or orientation byreceiving incident signals from signal sources in the environment. Bysuch a method, the positions and/or orientations determined for thecreature may be recorded for mapping of the movement of the creaturerelative to the environment and/or the relative movement, i.e. movementrelative to the previous position and/or orientation of the creature.

[0025] A second object of the present invention is to provide a methodfor locating a phenomenon in an environment, which method reduces thedisadvantages associated with such already known methods to asubstantial extent, i.e. to provide a method which enables the locatingof different types of each phenomenon without any need of aninstallation of a certain kind of sensor for phenomena and/or ofcameras, and which method is able to locate phenomena and also suchunexpected phenomena with great accuracy as regards the position and/ororientation of the phenomena.

[0026] This object is attained according to the invention by a methodfor locating a phenomenon in an environment, comprising that a creatureis connected to a locating member including a transducer connected to acomponent intended for pointing out phenomena in the environment, thatthe pointing component is directed by the creature towards thephenomenon from at least one pointing position, the transducerdetermining its position and/or orientation by receiving incidentsignals from signal sources in the environment and thereby determiningthe position and/or orientation of the pointing component relative tothe environment for said at least one pointing position, and that theposition and/or orientation of the pointed-out phenomenon relative tothe environment is determined by means of the position and/ororientation determined for the pointing component. By such a method, andif necessary use of further information about the nature of theenvironment in the form of for example a model, it is possible todetermine the position and/or orientation of said phenomenon relative tothe environment with great accuracy. Furthermore, it is possible todetermine that the creature has or has had a certain position and/ororientation relative to said phenomenon. The pointing component may forexample be provided with equipment for transmitting a laser beam andthereby the pointing component may be directed towards the currentphenomenon with great accuracy. Thus, information about the positionand/or orientation of the phenomenon may be obtained with greataccuracy, which is of great value in many applications such as forexample when the state of a certain equipment in the environment isdetected. For example, determining where a damage of a machine ispresent, a leaking water pipe, a fire etc. By the method for example aleakage of a roof may be pointed out in a repeatable way, which meansthat the position for the defect of the roof which caused the leakagemay be pointed out, and/or drawn on for example a CAD-drawing, whendropping from the ceiling, rainwater for instance, is noticed and thenat a later moment when the dropping is not present, or when droppingfrom several other positions are present, the position of the defect maybe pointed out again by means of the pointing component and theinformation from the occasion when the dropping was pointed out in thefirst place.

[0027] A third object of the present invention is to provide a method bywhich it is possible to use abstract stations as control stations forverifying that a phenomenon is present or has been present in a certainposition and/or orientation at a certain point of time.

[0028] This object is attained according to the invention by a methodfor determining if the position and/or orientation of a phenomenonrelative to the environment is in accordance with a reference,comprising that a creature is connected to a locating member including atransducer so that the relative positions and/or orientations of thecreature and the transducer are arranged to be within a limitedinterval, that the reference is defined by the introduction of at leastone condition regarding the position and/or orientation of the locatingmember relative to the environment, that the position and/or orientationof the locating member relative to the environment is determined bymeans of the transducer by receiving incident signals from signalsources in the environment, and that the position and/or orientationdetermined for the locating member is compared with a reference so thatat least some possibly occurring state in which said at least onecondition is fulfilled may be recorded. By such a method it is possibleto easily and rationally define a lot of different paths which can notbe predicted and which may be created in a random way or in a way chosenaccording to the present needs.

[0029] According to a preferred embodiment of the method according tothe invention for determining if the position and/or orientation of aphenomenon relative to the environment is in accordance with areference, the locating member is put by the creature into mechanicalcontact with an object in the environment for fixing the locating memberor a part thereof, and thereby the transducer, relative to the object sothat said at least one condition is fulfilled. By such a method, it ispossible to determine for example that a window is closed, that a dooris open or that a handle is in a certain position by the fact that thecreature places a locating member so that the transducer is fixedrelative to the object, the position of which is to be determined. Inthis connection, by means of the transducer, it may be determined wherethe locating member is present, and thereby where the creature ispresent, relative to the environment, for example, where in a room, sothat it is secured that the right object is checked, and determined iffor example the position and/or orientation of an object relative to theenvironment corresponds with the intended position and/or orientation ornot.

[0030] The fourth object of the present invention is to provide a methodfor determining and/or adjusting the position and/or orientation of anobject relative to an environment.

[0031] This object is attained according to the invention by a methodfor determining the position and/or orientation of an object relative toan environment by means of a creature, comprising that the creature isconnected to a locating member including a transducer, that the locatingmember is put by the creature into mechanical contact with the object,that the position and/or orientation of the locating member relative tothe environment is determined by means of the transducer by receivingincident signals from signal sources in the environment, and that theposition and/or orientation of the object is determined by means of theposition and/or orientation determined for the locating member. By sucha method it is possible to for example determine the position of anobject or perform adjustment and/or calibration of the object.

[0032] Further advantages and advantageous features of the invention aredisclosed in the following description and remaining dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Preferred embodiments of the invention are described below by wayof example only, and with reference to the attached drawings.

[0034] In the drawings:

[0035]FIG. 1 is a perspective view of an environment in the shape of aroom in a museum including a number of pictures and a visitor of theroom,

[0036]FIG. 2 is a schematic perspective view of a transducer accordingto the invention, and on the transducer incident signals occurring fromsignal sources in the environment,

[0037]FIG. 2a is a perspective view of a transducer according to theinvention comprising a wide-angle lens and a detector surface,

[0038]FIG. 3 is a block diagram of a device according to the inventionand examples of communication lines between components possibly includedin the device,

[0039]FIG. 4 is a view from above illustrating an exhibition hall and avisitor thereof,

[0040]FIGS. 5a, b and c are illustrations of possible appearances of adisplay for transferring information carried by the visitor of theexhibition hall in FIG. 4,

[0041]FIG. 6 is a view from above illustrating a path to be walked by aguard in a building and a guard,

[0042]FIG. 7 is a perspective view of an environment in which a personlocates a leakage of a pipe,

[0043]FIG. 8 is a view according to FIG. 7 in which the person has movedto another position relative to the environment,

[0044]FIG. 9 is a perspective view of a pipe and a valve arrangedthereon and a locating member to be applied on the handle of the valve,

[0045]FIG. 10 is a view from above illustrating an industrial estatewhich is subject for searching by means of a dog, and

[0046]FIG. 11 is a view illustrating a bracelet applied on a person andintended to work as an electronic tag.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

[0047] The locating member referred to in this application may in itssimplest design be constituted by a transducer for receiving signalsincident from signal sources in the environment and a means forconnecting the transducer and a creature to each other.

[0048] The connecting means may be for example, a glue, or a bag forcarrying the transducer or a band accommodating the transducer whichband is intended to be applied on the creature, such as a collar,bracelet or the like. However, it should be emphasised that theconnecting means may be included in the transducer itself and beprovided by the design of the transducer without using any component inaddition to the transducer. As an example, the transducer may beprovided with a connecting means in the form of a “handle” so that thetransducer may be connected to the creature for example by the fact thatthe creature quite simply grasps or bites the transducer. The transducermay also be designed to be implanted in the creature.

[0049] Another type of connecting means is different kind of vehicles.In this connection, the creature and the vehicle are arranged so thatthe relative positions and/or orientations of the creature and thevehicle are arranged to be within a limited interval by the fact thatthe extension of the vehicle is limited or by the fact that the creatureis fixed to the vehicle. The transducer may be arranged on for example acar in which the creature is present or on a boat on which the creatureis present.

[0050] It should also be emphasised that the term environment defined inthe introduction in its simplest embodiment may comprise only the signalsources from which the transducer is intended to receive signals for theposition- and/or orientation determination, which will be describedfurther below.

[0051] Even if it is not described in detail for all embodiments, it ispointed out that for all applications and embodiments described herein,signal sources in the environment is used for transmitting, reflectingor spreading signals which signals are received by a transducer with thepurpose of determining of the position and/or orientation of thetransducer. Furthermore, throughout the description, similar referencenumerals denote same or analogous objects.

[0052] To avoid misinterpretations it is emphasised that the meaning ofthe term “to locate” a phenomenon or the like is in the first place todetermine the position and/or orientation of the phenomenon relative tothe environment or to trace the phenomenon in the environment, althoughif the invention also may be used to locate, in the meaning of put intoa position, a phenomenon in a certain position and/or orientationrelative to the environment.

[0053] In FIG. 1 an environment, which is constituted by a room 1, someof the limiting surfaces of the room 1 and a number of things 2 presentin the room 1, is illustrated. Although, in this case, the environmentis a schematically depicted room 1 in a building, in practice, theenvironment may be any indoor- or semi-indoor environment having severalproperties. In this embodiment, the environment is thought to be amuseum room 1 and the things occurring in the room 1 pictures 2. Avisitor 3 of the museum is present in the room 1. According to theinvention, the visitor 3 is provided with a device for determining itsposition and/or orientation relative to the environment. The devicecomprises a locating member 4 connected to the creature 3 which locatingmember includes a transducer 5 arranged to determine its position and/ororientation relative to the environment. The transducer 5 included inthe locating member 4 is arranged on the head of the visitor 3.

[0054] In this connection, it is interesting to determine the positionof the person 3 relative to the room 1 as well as relative to separateobjects 2 in the room 1. In addition, the transducer 5 enablesdetermining of the orientation of the person 3. By the transducer 5located on the head of the person 3, besides the position information,also information about how the head is turned relative to theenvironment, is obtained, which indirectly gives information about theviewing direction of the person 3.

[0055] In addition to the transducer 5, the locating member 4 includesearphones 6 and a microphone 7. Preferably, the transducer 5, theearphones 6 and the microphone 7 are arranged in a so-called headset toenable the user to utilise the equipment in a comfortable way. Thus, theheadset mentioned above constitutes a means 8 by which the person 3 andthe transducer 5 are connected so that the relative positions andorientations of the person 3 and the transducer 5 are arranged to bewithin a limited interval. Thus, by means of the information about theposition and/or orientation of the transducer 5, the position and/ororientation of the person 3 may be determined.

[0056] Furthermore, the transducer 5 is arranged to receive incidentsignals from signal sources 9 in the environment, which signalspropagate rectilinearly between the signal sources 9 and the transducer5, for achieving the position- or orientation information and thetransducer 5 is arranged to repeatedly determine its position and/ororientation relative to the environment when the transducer 5 and theenvironment are moved relative to each other, i.e. when the person 3moves. Furthermore, the transducer 5 is arranged to be freely movableand mechanically unguided by the environment in an arbitrary coordinatesystem by the carrier of the transducer.

[0057] With the expression that the position of a thing or of a creatureis determined in this application is intended that at least some of theposition parameters (x, y, z) is known in a coordinate system, therelation to the environment of which is known. By the expression thatthe orientation of a thing or of a creature is determined in thisapplication is intended that at least one of the orientation parameters(α, β, γ) is known in a coordinate system, the relation to theenvironment of which is known. Depending on the current application ofthe invention by the expression the position and/or orientation of thecreature in some cases is intended the position and/or orientation ofthe creature in its entirety and in some cases the position and/ororientation of a particular part of the body of the creature. In oneapplication, it may be sufficient to know for example where a humanbeing is present and in another application information about forexample how the head or the hand of a human being is turned relative tothe environment or, particularly, relative to the rest of the body maybe required. The number of transducers/locating members and theirposition on the creature depends on these desires to a great extent.

[0058] Usually, the transducer is arranged to determine its positionand/or orientation with respect to at least two degrees of freedomrelative to the environment. This is the case for example when theposition of a creature or a thing is to be determined with respect totwo position parameters. In the example illustrated in FIG. 1, theposition of the person 3 is suitably determined with respect to at leasttwo position parameters for recording the position of the person 3 in acertain horizontal plane, for example where on the floor the person 3 ispresent, and with respect to at least one orientation parameter forrecording the direction of the person 3 in the environment, for examplein which direction the head of the person 3 is directed or more closelyhow the head is turned about an axis perpendicular to the horizontalplane. In using the transducer 5, which determines more degrees offreedom, it is also possible to determine for example in whichhorizontal plane the person 3 is present as well. The current horizontalplane may vary, for example if the person 3 visits different floors orif the current person 3 bends down and straightens himself up,respectively. With knowledge about a further orientation parameter, howthe head of the person is leaned, i.e. its rotation angle relative tosaid axis which is perpendicular to the horizontal plane, may also bedetermined. For obtaining complete information about the position andorientation of the person 3 (of the head) all position- and orientationparameters have to be determined.

[0059] For determining four degrees of freedom related to the room ofthe transducer 5, at least two signal sources 9 are required, and inmost cases, at least three signal sources 9 are required. A use of onlytwo signal sources 9 requires simple cases, for example by the fact thata favourable symmetry is present, or that certain position- andorientation information may be obtained in another way, for examplethrough a model of the environment. In the case it is desired todetermine all the six degrees of freedom, at least three, often foursignal sources 9 are required. In most cases it is an advantage to use agreat number of signal sources 9 independent of how many degrees offreedom that is desired to determine, since a great number of signalsources 9 secures that the smallest number of signal sources 9, which isrequired for transferring the signals to the transducer 5, always isobtained, even if some signal source or a few of the signal sourceswould be blocked out. These signal sources 9 may be placed in theenvironment for this special reason, but they may also be constituted byobjects naturally occurring in the environment.

[0060] One type of transducer 5, which may be used in the devices foraccomplishing the methods according to the invention, has been developedand introduced into the market by MEEQ AB, Hässlögatan 20, SE-721 31Västerås, Sweden.

[0061] With the measuring method described in this application and inthe Swedish patent No. 444530, 458427 and 506517 it is possible toperform measurements, i.e. to determine position and/or orientation witha great accuracy. In some cases with an accuracy in the magnitude oftenth of millimetres, or better, as regards position and tenth of amrad, or better, as regards the orientation. Furthermore, by the factthat the incident directions of incident signals are recorded, and bythe fact that the transducer knows its own position and orientation aswell as the positions of the “desired” signal sources, there is apossibility to sort out “false signals” originated from for examplenon-desired signal sources, alternative signal sources or reflectedsignal sources. By using more than the smallest number of signal sourcesrequired also disturbances in the form of obscured signal sources may behandled by the equipment without effecting the accurancy to anyappreciable extent. Besides that the transducer records the incidentdirections of the signals for the different signal sources in the waymentioned above, thus, also reflected signals which incident differentlyon the transducer and originate from one and the same signal source, maybe registered separately, and thereby undesired signals, also such asoriginate from one and the same signal source, may be dropped in thefurther evaluation of the signals.

[0062] When the invention is applied, it is suitably proceeded so thatbefore the user utilises the equipment, the transducer 5 is brought toreceive signals from at least two, preferably three or four, and usuallyfrom five or more signal sources 9, which define the coordinate systemof the environment, by that the transducer 5 is moved throughout theroom 1, until the transducer 5 has received sufficient information aboutthe positions of the signal sources 9, i.e. about the coordinate systemof the environment, which may be performed by hand by a person 3 oranother creature 3 or by means of a vehicle, a freely movable robot orthe like. If, in addition, it is required that during the subsequentuse, the absolute scale of length shall be known, the measuring of thesignal sources 9 is performed while simultaneously using a measuringstandard, for example by placing an object with well known dimensions asa reference gage in the environment during the measuring procedure.

[0063] The transducer 5 may be a two-dimensional transducer of the kindwhich is described in the Swedish Patent No. 444530. Thus, thetransducer may be an optical instrument, which works with “opticalsignal”, which in this application refers to signals which areconstituted by, or utilised, optical radiation within as well as outsidethe band of visible wavelengths. The wavelength range, which ispreferably intended, is in the interval 10-15 000 nm. Suitably, thewavelength range 200-1600 nm may be applied, but it should be emphasisedthat the invention is not in any way restricted to this wavelengthinterval. A number of signal sources 9, for example in the form of lightemitting diodes, may be arranged at a distance from the transducer andfrom each other, so that in normal use of the transducer, always atleast three, preferably four of the signal sources simultaneously maytransfer signals to the transducer. The positions of the signal sourcesrelative to each other are known, for example by measuring the positionsof the sources in a coordinate system common to the sources, whichmeasuring may be performed by means of the transducer. Concerningmeasuring of the positions of the signal sources in general reference ismade to the Swedish Patent No. 506517.

[0064] Furthermore, the locating member 4 suitably comprises a means 10for internal communication between the components: the transducer 5, themeans 6 for transferring information from the locating member 4 to thecreature 3 and the means 7 included in the locating member 4 forreceiving information from the creature 3. The communication means 10may have a local computer unit 11 and other standard components requiredfor signal processing, signal transferring and storing of information.See also FIG. 3. Preferably, the device comprises also a means 12 forexternal communication between the locating member 4 and for example acentral computer unit 13. The communication, both internally andexternally, may be performed by signal transferring via wire or awireless link. Although, the means 6 for transferring information fromthe locating member 4 to the creature 3 in the described example, isconstituted by loudspeakers 6 located in the earphones 6, many otherinformation transferring means may be used and certain of these will bedescribed in connection to other embodiment examples. This is also truefor the means 7 for receiving information from the creature 3, whichmeans not necessarily needs to be a microphone 7.

[0065] The transducer 5 is in connection with a calculation unit via acommunication channel, which calculation unit may be included in thecomputer unit 11 arranged in the locating member 4 or in the centralcomputer unit 13. The communication channel may be constituted by aflexible cable as mentioned above, or—for allowing as large freedom ofmovement as possible to the operator—by a wireless link, for example anIR-link or a radio-link, for example “Bluetooth” technique from EricssonComponents AB in Kista, Sweden. Through this channel, informationconcerning how the different signals from the signal sources 9 incidenton the transducer 5 is delivered to the calculation unit from thetransducer 5.

[0066] The calculation unit continuously calculates position andorientation of the transducer 5. In one embodiment of the device, thetransducer 5 is designed to receive transmitted signals from the signalsources 9 and record the relative incident directions of the signalsreceived in relation to the transducer 5. This does not need to beperformed by using optical signals, but may also be performed by usingfor example microwaves or acoustic waves and antenna arrays, so calledphased arrays. The transducer may for example be a radar unit designedfor transmitting radar waves and receiving radar echoes from signalsources in the environment. Based on the incident directions of theradar echoes, the calculation unit may then calculate the position andthe orientation of the transducer, and thereby the position and theorientation of the object connected to the transducer.

[0067] Phased arrays for microwaves available on the market are providedby for example Ericsson Microwave AB, Mölndal, Sweden and by othersuppliers of microwave equipment. Phased arrays for ultrasound areprovided by for example the subsidiary company KrautKramer UltrasonicSystems, Cologne, Germany, of the group of companies named AGFA.

[0068] In some cases the transducer has a surface designed to receivetransmitted signals from the signal sources and to record the relativeincident directions of the signals received in relation to the surfaceand/or the relative incident positions of the received signals on thesurface. In this case, for example a lens may be used for depicting theenvironment on a surface. For example, a video camera of CCD-type and awide-angle lens may be used as a transducer.

[0069] In FIG. 2 it is schematically illustrated how signals from threesignal sources 9 incident on the transducer 5 and how the incidentangles of the received signals are related to each other. The incidentdirection for respective signal is defined by φ_(i) and θ_(i), wherei=1, 2 or 3. The incident directions are then the basis for calculatingthe orientation- and position information required.

[0070] As an example, in FIG. 2a, a wide-angle lens 50 and a surface 51for detecting the signals are illustrated. A signal from a signal source9 in the environment which incidents on the wide-angle lens is depictedon the detector surface at a position which corresponds to the incidentdirection φ, θ of the signal relative to the transducer 5. By detectinga unique position, i.e. its relative x, y-coordinates on the detectorsurface, the incident direction φ, θ of the signal may be derived, i.e.the direction of the sight line from the transducer to the currentsignal source may be determined.

[0071] Briefly, the orientation- and the position calculation may inthis case be performed by that three, in general four, signal sources 9are selected, the directions relative to the transducer 5 of the sightlines from the transducer 5 to these signal sources 9 are determined,the position and orientation of the transducer 5 being obtained by usingthe directions of the sight lines, and the known positions of the signalsources 9 and geometrical relations between these quantities. Thepositions of the signal sources 9 relative to each other, are assumed tobe known. Alternatively, the relative positions of the signal sources 9may be known indirectly through that the position of each source isknown in a coordinate system.

[0072] Advantageously, the signal receiving direction area which isconstituted by a solid angle and which is formed by the collected amountof signal receiving directions from which the transducer is arranged toreceive incident signals from said signal sources, of the transducer, isat least 0.2 steradians, otherwise it is difficult to maintain theperformance concerning the determinations along the axis of thetransducer, i.e. in the main direction of the transducer, so that thisis in parity with the two other axes of the transducer. However,preferably this signal receiving direction area is at least 1 steradian,and the larger such area, the fewer number of signal sources arerequired in the environment to obtain a certain accuracy in thedetermination of the orientation and the position of the transducerrelative to the environment. The more objects which move in theenvironment, and the more complicated geometry of the environment due tofor example protruding boxes, oblique corners and other things thatobstruct, the larger said signal receiving direction area should be, andin a workshop with a lot of movable parts it may be advantageous to havea signal receiving direction area exceeding 4 steradians, and stillpossibly more than 100 signal sources may be needed in the environmentfor attaining a reliable determination of the orientation- and positioninformation for the transducer. In that case, it is also preferred thatthe signal receiving direction area is topologically connected, even ifthis is not any definite necessity.

[0073] Said signal receiving direction area may have any shape andspreading over the imagined solid angle sphere. According to a preferredembodiment of the invention, the signal receiving direction area of thetransducer is topologically connected, which however includes that itcould have enclosed direction areas without signal receiving capability.The signal receiving direction area is independent of external factorsand relates only to the receiving directions of the transducer. It isnot affected by limitations in the form of external blockage ofdirection areas or any partial absence of signal sources.

[0074] It is preferred that the signal sources are well spread outwithin the signal receiving direction area of the transducer, since thisimproves the probability that an arising disturbance, such as obscuringof some part of the environment through persons, fork lifters, robots orsimilar, does not prevent achieving of correct information, even if thenumber of signal sources in the environment are kept on aproportionately low level. However, it is really the design of thedevice according to the invention, especially with a broad signalreceiving direction area, that makes such a well spreading not asimportant as in previous known devices of this type.

[0075] About the signal receiving direction area the following may beadded:

[0076] A signal receiving direction area comprising less than 0.2steradians is for natural reasons difficult to use in practice, since insuch a case a small number of objects blocking in the environment mayeasily disturb the transducer so it does not work. In addition, in thecase of such small signal receiving direction areas the number ofrequired signal sources in the environment becomes impracticably largeand it is that which in practice restricts the user. In addition, withsuch small, particularly if they are connected to each other, signalreceiving direction areas, it will be difficult to maintain the samehigh measuring accuracy of positions in all position measuringdirections.

[0077] Preferably, the signal receiving direction area should exceed 1steradian, so that the number of required signal sources becomesreasonably large and so that a fairly uniform measuring accuracy ofpositions then may be obtained.

[0078] If the environment is geometrically complex, with for examplemany and possibly movable objects, reflecting/mirroring surfaces and/ortransducer positions in the vicinity of big objects without signalsources, where a typical such an environment may be a film studio inwhich many persons, cameras, props, side-scenes, mirrors and vehiclesare present at the same time, the signal receiving direction area shouldexceed 2 steradians. A further reason for a larger signal receivingdirection area is that the transducer shall not have a restrictedworking range as regards firstly orientations because of large hiddensectors without signal sources. Particularly, in complex environmentswhere it occur large objects blocking signal sources and the number ofsignal sources is limited, also signal receiving direction areas, whichexceed 4 steradians, are desired.

[0079] The distribution of signal sources over the working range maypreferably be adapted to the requirements of measuring accuracy indifferent parts of the environment and to the nature of the environment.This considerably facilitates the possibility to use signal sourcesnaturally occurring in the environment. The need of the number of signalsources certainly depends on also the signal receiving direction area ofthe transducer, in accordance with the above mentioned, since thesmallest number of signal sources recorded by the transducer in thenormal case must be equal to or exceed 4. An increased number of signalsources give, however, both higher accuracy and improved durabilityagainst further disturbances.

[0080] The construction of a transducer and the construction of thecorresponding calculating circuits and the function thereof are asmentioned before more closely described in the above mentioned SwedishPatent No. 444530.

[0081] The signal sources 9 may be active signal emitting sources, suchas light emitting diodes or the like, the light of which may possibly bepulsated or modulated, or passive signal sources 9 such as reflectingmarkers made of for example reflecting tape. The markers may be planefigures or—to show the same shape independent of the viewingdirection—be constituted by reflecting spheres. Furthermore, the markersmay have different shapes in relation to each other to make it easy forthe calculation unit and the signal processing circuits thereof toidentify and keep apart different markers and alternatively, with thesame purpose, markers with the same shape but with different sizesand/or “colour” may be used, the colour term including also not visibleparts of the electromagnetic spectra. In the use of passive reflectingsignal sources 9, the device may include means for transmitting ofsignals intended to be reflected by the reflecting markers. Thetransmitting means, which in such a case suitably are arranged inconnection to the transducer 5, may transmit infrared light forinstance, preferably pulsated or modulated with a certain frequency tobe able to separate the current signals from interfering light sources,for instance.

[0082] In an alternative embodiment no specially arranged signal sourcesare required, but as signal sources are used suitable details alreadypresent in the environment. Examples of suitable details are corners,holes and similar, which have a characteristic appearance and welldefined and known positions. When the device is started these detailsare pointed out and identified in a suitably way, and their positionsare determined and stored, for example through downloading from aCAD-system, or alternatively they are measured by the transducer. Thedetails used as signal sources may be illuminated only from regularlights in the room, but certainly special light sources may be arrangedto give the illumination the desired intensity or character if required.Certainly, at least some of the signal sources may be constituted byspecially arranged markers, for example, by portions, patterns orfigures of light tape placed on a dark background. In the Swedish patentnumber 458 427 it is closer described how the position and orientationof a transducer of this type may be calculated, as well as theconstruction and the function of an equipment for performing thiscalculation.

[0083] A certain set of defined signal sources 9 included in anenvironment may be said to constitute a certain reference system inwhich the locating member 4 including the transducer 5 works. When acreature 3, provided with the locating member 4, enters such a referencesystem for cooperating with the signal sources 9, this is referred to asthe locating member 4 approaches to the reference system and thereby aparticular reference coordinate system. In approaching the system, thereis different ways to obtain the information about the reference systemrequired for the calculating unit. Suppose that a reference system hasan extension corresponding to, for example, a larger building, such as amachinery room, in which a service person will move and perform certainactions. Thus, throughout the machinery room there are a lot of signalsources defined. Furthermore, the machinery room may as usual beprovided with a number of entrances at which it is possible to pass intoand out of the machinery room. If the service person connected to thelocating member intends to go into the machinery room, to be able toapproach the reference system in the general case, it is required thatthe calculating unit connected to the transducer receives informationabout where the service person enters the machinery room, i.e. theinformation about from which signal sources the transducer receivessignals. This information may be received in a passive way or beobtained in an active way. Passive transferring of information may beperformed by placing the signal sources, which are located for exampleat the entrance, so that they form a unique “pattern” for the referencesystem. The calculating unit recognises the pattern and may determinewhich reference system which will be used, and the entrance throughwhich the service person will pass, or has passed, into the machineryroom. When information is transferred in an active way, a transmitter,either a separate transmitter or one of the signal sources, may belocated at the current entrance and when the service person passes thistransmitter, the required information about the reference system istransferred to the calculating unit by receiving transmitted signalsfrom the transmitter.

[0084] There is also possible to utilise other information sources forobtaining information about, for example, the position and/ororientation of a creature relative to the current reference system. Forexample, outdoors a GPS may be used for determining the positions of theservice person when he/she is on the way to the machinery room. At theentrance to the machinery room, the local reference system takes overthe navigation. In this connection, the position determination by GPSmay be used to assist the calculating unit with certain initialinformation, such as at which building, door, etc. the creature ispresent, in the transition to the local reference system.

[0085] In the local reference system, one or more sub-reference systemsmay be arranged. With the machinery room as an example, this may involvethat some object in the machinery room, such as a particular machine,has its own reference system. The reason for that may be for examplethat for different positions and/or applications, differentcharacteristics of the reference system are required. For example, thesub-reference system may be able to be rearranged or movably arrangedrelative to a superior system. Thus, in different local referencesystems or sub-reference systems, the number of signal sources, thelocations of the signal sources, the type and function (active, passive,set out etc.) of the signal sources, may be varied to satisfy thecurrent need. When moving inside the machinery room, possibly arelatively simple reference system is sufficient, whereas possibly amore advanced reference system around the machine at which the serviceperson will perform inspection, adjustment, repair or the like, isrequired.

[0086] In FIG. 3 a block diagram, from which the different componentsand the corresponding communication lines of one embodiment of theinvention appear, is illustrated. The locating member 4, including thetransducer 5, the means 7 for transferring information from the creature3 to the locating member 4, the means 6 for transferring informationfrom the locating member 4 to the creature 3, and the local computerunit 11, may communicate with the external central computer unit 13.Furthermore, it appears that the transducer 5 obtains informationrequired for the position- and orientation determination from signalsources 9 in the environment. The creature 3 is mechanically connectedto the transducer 5. The computer unit 11 receives information from thecreature 3 via the information receiving means 7, for example amicrophone or a inputting unit, such as a key set, and transfersinformation via the information communicating means 6, for example aloudspeaker or a display. Certainly, it is also possible to arrange theinformation transferring means in the form of one unit, such as acombined communicating and inputting unit. In FIG. 3, the fact that thelocating member 4, as well as the central computer unit 13, may beconnected with other objects 14 in the environment for transferringsignals, is also illustrated. Furthermore, it is of course possible thatone or more further objects are included in the locating member 4.

[0087] The use of the invention for determining the position and/ororientation of a creature 3, applied on the embodiment described withreference to FIG. 1 comprises that the position and/or orientation ofthe visitor 3 relative to the environment, is determined by connectingthe person 3 to the locating member 4 including a transducer 5 so thatthe relative positions and/or orientations of the person 3 and thetransducer 5 are arranged to be within a limited interval, thetransducer 5 determining its position and/or orientation relative to theenvironment by receiving incident signals from signal sources 9 in theenvironment, and that the position and/or orientation of the creature 3is determined by means of the position and/or orientation determined forthe transducer 5. This is repeated continuously when the person 3 movesrelative to the environment. The determination of position and/ororientation is always performed relative to the environment, but such aspreviously described, in some cases the environment may be constitutedby the signal sources 9 only, and consequently, in such a case it isprimarily the position and/or the orientation of the creature 3 relativeto the previous position and/or orientation of the creature whichprimarily is determined.

[0088] In the embodiment example illustrated in FIG. 1, where a humanbeing visits a museum, the invention may be utilised in a way so that atthe visit, the person 3 may receive information about different pictures2, which are looked at by the person. By the fact that the transducer 5continuously may determine the position and orientation of the person 3in the room 1, the (central) computer unit 11, 13 may receiveinformation about when the person 3 looks at a certain picture 2 and inaccordance with this information transmit for example a sound message tothe observer which contains information about the artist, origin,painting technique, etc., of the picture 2. When works of art which givedifferent experiences depending on the viewing direction are observed,the transferring of information, for example in the form of music orother sounds, may be adapted depending on the current viewing direction,to reinforce these characteristics of the piece of art. Furthermore,visitor 3 may receive information about how he/she should move relativeto the environment to get to a position and/or orientation relative tothe current object, which position and/or orientation leads to forexample that a particular experience is attained.

[0089] The invention may be used in a similar way also for a guard whichis assigned for a task of checking the building and see to that allpictures are present in their right positions or for a service personwhich are going to do for example technical installations. For thispurpose, the guard does not need to know if there should be a picture ina certain position or not. It is sufficient that the guard follows giveninstructions and indirectly or in an active way, reports what he/sheobserves in certain given positions and viewing directions, and therebysomeone/something which obtains information from the (central) computerunit may evaluate the information and decide if everything is in dueorder. When the guard moves, the movement thereof may be directed on thebasis of or by means of the position- and/or orientation information.For example, an operator at the central computer unit may giveinstructions continuously to the guard how he/she shall move or lookduring movement along the path the guard has to walk. These instructionsmay also be pre-recorded in the case an unmanned a central computer unitis used. At the same time as it is possible to check or effect thestatus of an environment by means of the invention, for example,switch-on/switch-off light when the guard passes a certain position, ofcourse, it is also possible to check that the guard follows hisinstructions as regards paths of movement and the actions which have tobe performed. In this connection, the positions and/or orientationsdetermined for the guard may be recorded for mapping the movement of theguard relative to the environment, and/or relative to his previousposition and/or orientation. Preferably, in this case abstract stationsare used.

[0090] The invention may also be utilised by an artist or a museumsuperintendent for obtaining information about the activity of thevisitors in the building and/or for designing suitable guiding routinesfor the visitors. Thus, it is possible to programme the computerunit/computer units 11, 13, so that a visitor 3 continuously is givenrelevant information based on the position and/or orientation of thevisitor 3 and/or the desires of the visitor 3. When creating such avisitor routine, the artist himself may move in the current environmentwhile utilising the equipment according to the invention and when he/sheis present in particular positions and/or orientations, he/she may forexample record an announcer text that a visitor 3 then may have playedin the earphones 6 when the visitor, within certain given tolerances, ispresent in the corresponding position and/or orientation. There is alsoa possibility to store information about which pictures 2, which havebeen looked on, and to which extent, from which viewing directions anddistances, etc. This information may be used in different ways, forexample by art-dealers for determining which object that are popular andhow the position of the object relative to the room effects theexperiences, etc., of the visitor.

[0091] Particularly, it should be emphasised that the example regardinga museum illustrated in FIG. 1 is only to be regarded as just an exampleand that several equivalent applications of the invention are foundwithin a number of different fields. For example, the invention could beused in different shops and shopping centres. Instead of pictures, forexample articles and/or signboards are then objects which firstly are ofinterest to a visitor to study. In this connection, a customer couldreceive continuos information about different articles when he/she ispresent in a particular position and/or looks in a certain direction andinformation about suitable paths of movement to find the desiredarticles. The shopkeeper has in the same way as the museumsuperintendent also a possibility to evaluate how a customer has beenmoved and looked at the different articles and to which extent so hasoccurred to be able to optimise the design of the shop on the basisthereof with the purpose of increasing the sale and/or satisfy differentdesires of the customers. Furthermore, in a similar way as in the caseof the museum, different visitor routines may be pre-programmed, and/orcreated on-line, in accordance with the desires of theshopkeeper/visitor. An alternative to headset is that the transducer inthis case is arranged on a shopping trolley and that the customer ismechanically connected to the transducer by the fact that he/she quitesimply holds the shopping trolley.

[0092] A further variant of this application of the invention isillustrated in FIGS. 4 and 5. In FIG. 4, an environment in the shape ofan exhibition hall is illustrated. In this embodiment, the visitor 3 ofthe exhibition is provided with substantially the same equipment as inthe example according to FIG. 1, but in this case the locating member 4comprises also a representation and/or inputting unit 15, which may befor example a portable display designed to communicate with the otherequipment. The visitor 3 of the exhibition may have information via thedisplay 15 about how he/she should move, and/or communicate desireshimself/herself, such as how he/she desires to move, to take part ofwhat is illustrated in the exhibition hall in the best way, to find alavatory or the like. In FIGS. 5a, 5 b and 5 c, an example of what couldbe displayed on the display when the visitor 3 of the exhibition ispresent at the points denoted with A-C in FIG. 4 is illustrated. On thedisplay, several things may be displayed, such as which direction ispointing to the north, which direction the visitor 3 should choose tofollow a certain route and/or reach a certain goal, or information ofanother kind to attract the visitors 3 attention or inform he/she and/orsupply commercial advertising.

[0093] In FIG. 6 a guard 3 on his guard path 16 is illustrated and FIGS.7 and 8 illustrate how a guard 3 or a service person 3 identifies andreports a damage in a construction, more precisely, in the embodimentexample the matter is a leakage of a pipe.

[0094] The case with the guard is in many ways analogous to the case ofthe museum/store, which is illustrated in FIG. 1. An importantdifference regarding how the equipment is used is however that in theprevious example, the (central) computer unit 11, 13 suitably works as a“slave” and the visitor/customer 3 has a “master”. In the guard case onthe contrary, the conditions are the opposite, i.e. the guard 3 is“slave” and the (central) computer unit 11, 13 is the “master”. Theterms master and slave are used to indicate who or what is in control,which means for example that the guard 3, which is slave, is controlledby the (central) computer unit 11, 13, to go to a certain position forinstance, whereas the visitor 3, which is master, freely chooses hispath 16 of movement assisted by the (central) computer unit 11, 13 andto the extent desired controls which information he/she will receivefrom the computer unit/units.

[0095] In the guard case the (central) computer unit 11, 13 may be usedto generate a guard path 16 with or without intervention by the guard 3.The guard 3 does not need to receive any prior information about thecurrent guard path 16 or what will happen along the path. In thisconnection, the guard 3 is guided in the same way as, for example, avisitor 3 in previously described embodiments, towards a given goal, butthe goal is predetermined by the (central) computer unit 11, 13, or isdetermined thereby and/or by an operator of the (central) computer unit11, 13 and thus, not by the guard 3 himself. It can be arranged, forexample, so that two patrolling guards are met without that the guardsare informed thereof in advance. Furthermore, other guard duties may beintroduced, such as that the guard when passing an object in theenvironment, for example a machine, has to take a special action todocument the status of this object.

[0096] For the sake of clarity, in the example illustrated in FIG. 6, adashed line and arrows illustrate the path 16 of movement of the guard3. In addition, some critical points along the guard path 16 are denotedA-F. The guard 3 is intended to receive information via the locatingmember 4 about how he/she shall move and which actions that have to beperformed. For this purpose, besides the previous mentioned means fortransferring information between the creature 3 and the (central)computer unit 11, 13, the locating member 4 may also include a displayunit portable by the guard 3. This means that the commands to the guard3 along the guard path 16 could be transferred visually and/orauditorially and could have the following meaning: at points A and F;turn to left 90°, at points B, C and E; turn to right 90°.

[0097] If the guard 3 in violation of the present instructions, forexample at the point A, instead would go to the right, new informationmay be transferred from the (central) computer unit 11, 13 to the guard3 to correct the violation. In that connection, the guard 3 may receiveinformation about to return to the assigned route. It is also possibleto allow or deny the guard 3 authorisation. If the guard 3 in violationof the present instructions, for example at the point A, instead wouldgo straight forward into the area 17 marked with dashed lines,information with the meaning that in this area it is forbidden to be maybe transferred from the (central) computer unit 11, 13, to the guard 3and/or signals that for example a door 18 shall be locked to preventfrom passing may be sent from the (central) computer unit 11, 13 to areceiver in the environment for controlling the door lock.

[0098] In an arbitrary place and at an optional moment, the guard 3 maybe requested to place himself in a certain position and/or orientationand/or to perform a certain action. This may be performed for example toaccomplish a method for determining if the position and/or orientationof a phenomenon 22 relative to an environment corresponds to areference. The method comprises that a creature, in this case the guard3, such as previously described, is connected to a locating member 4including a transducer 5, so that the relative positions and/ororientations of the creature 3 and the transducer 5 are arranged to bewithin a limited interval and that said reference is defined by theintroduction of at least one condition regarding the position and/ororientation of the locating member 4 relative to the environment, andthat the position and/or orientation of the locating member 4 relativeto the environment, is determined by means of the transducer 5 byreceiving incident signals from signal sources 9 in the environment, andthat the position- and/or orientation information determined for thelocating member 4 is compared with the reference, so that at least onepossibly occurring state in which said at least one condition isfulfilled may be recorded. The locating member 4 including thetransducer 5 may, such as previously described, be such a member whichis brought by the creature 3 or a locating member including atransducer, which member the creature temporarily is connected to at thecurrent position. In the example illustrated in FIG. 6, the guard 3,when he/she is present at the point D, could be requested to placehimself in a certain position and/or orientation and possibly berequested to take some further action in connection therewith, forexample to go into a room 40 through the door located at the point D andby means of the transducer 5 determine that a switch 19 is in aswitched-off or switched-on position, and in that way obtain permissionto the marked area 17 and/or to cause that the door 18 at the point E islocked up, so that he/she may continue his guard path 16 to the point F.

[0099] Thus, in this embodiment, the invention includes said at leastone reference defined by the introduction of at least one conditionregarding the position and/or orientation of the transducer 5 relativeto the environment, but also other conditions, such as a certain pointof time, a voice test, etc., may be added. The introduction of thereferences according to the invention may be used as abstract stationswhich for example a guard is requested to visit, which gives a greatflexibility in the arrangement of for example guard paths. Although,walls 20 which form corridors in which the guard 3 moves are illustratedin FIG. 6, it is also possible to create “corridors”, “rooms”, or thelike, which are abstract and defined by certain position- and/ororientation coordinates by applying a specially designed authorisation.When applying such abstract environments, a person may move freelywithin a given zone, such as along a passage route in a workshop, but ifthe person turns off from the zone, an alarm is started and/or theperson receives instructions via the locating unit. Zones, which areallowed and not allowed, may be created, changed or removed in an easyway all according to the present need, and may be different fordifferent creatures.

[0100] With reference to previous described embodiments of theinvention, it may be mentioned that another application of abstractstation is that a person, for example a customer utilising the inventionat a visit in a shop, receives a bonus and/or a reduction of the priceif he/she visits certain abstract stations. At the abstract stations,for example an article may be exposed, and hereby a shopkeeper mayincrease the exposure to commercial in exchange for that the customerreceives a certain reward.

[0101] In some cases said at least one condition is defined by theposition and/or extension of an object 21 occurring in the environment.To secure that the guard 3 easily and rationally will be able to placethe locating member 4, i.e. the transducer 5, in accordance with thereference, the locating member 4 and/or the reference object may in somecases be designed to enable the locating member 4 and the object 21 toengage each other for fixing the locating member 4 or a part thereof,and thereby the transducer 5, relative to the object 21, so that thetransducer 5 fulfils said at least one condition. This may be applied todetermine, by means of the transducer, that for example a voltagebreaker is in a position which means that an area which otherwise isapplied voltage, is disconnected, so that a service person may pass thearea or perform work in the area, and after that the service person hasleft the area, to determine in a corresponding way that the breaker isin another position which means that the area is applied voltage.

[0102] In a similar way as in the examples of the museum and the shop,special guard paths may be established and if the required signalsources are present in the environment, a representative of thoseproviding the guard service and a representative of the buyer thereof,may move in the current environment while bringing one or more locatingmembers to together define and determine a guard path in accordance withthe desires of the customer. In this connection, there is possible todesign a certain guard service in situ and thus make an agreement aboutwhich actions that shall be included in the guard undertakings. Forexample, abstract stations and authorisations may be defined, routes andviewing directions, etc., for the guard 3 may be determined.

[0103]FIGS. 7 and 8 illustrate how a phenomenon 22 of an environment islocated. This application of the invention comprises that a creature 3is connected to a locating member 4 including a transducer 5 connectedto a component 23 intended for pointing out phenomenon 22 in theenvironment, that the pointing component 23 is directed by the creature3 towards the phenomenon 22 from at least one pointing position 26, thetransducer 5 determining its position and/or orientation by receivingincident signals from signal sources 9 in the environment and therebydetermining the position and/or orientation of the pointing component 23relative to the environment for said at least one pointing position, andthat the position and/or orientation of the phenomenon 22 pointed outrelative the environment is determined by means of the position and/ororientation determined for the pointing component 23. To accomplishthis, the locating member 4 includes the pointing component 23 portableby the creature 3 and mechanically connected to the transducer 5, whichcomponent 23 is to be directed relative to phenomenon 22 in theenvironment. A service person 3 directs the pointing component 23towards a leaking pipe 24. The pointing component 23 may include a means25 for transmitting directive electromagnetic radiation, such aslaserlight or the like. In this connection, the pointing component 23may be directed towards the current phenomenon 22 with precision at thesame time as the transducer 5 provides information about the positionand/or orientation of the pointing component 23 relative to theenvironment. Then, to determine the position of phenomenon 22, in thiscase the position of the leakage 22 of a water pipe, relative to theenvironment, the method may be repeated for one or more other differentpositions of the pointing component 23. Suitably, the service person 3confirms that such a pointing out action is desired to be recorded byverifying that the pointing component 23 is placed in a position inwhich a pointing out action shall be performed. Verification may beperformed in many different ways, for example by that the creatureeffects an activation component of the pointing component, such as abutton or the like, or by talking in a microphone connected to the(central) computer unit 11, 13 or by keeping the pointing componentstill during a certain period of time, etc.

[0104] In FIG. 8, the person 3 is illustrated in another position 27relative to the environment. By means of the information about theposition and the orientation of the pointing component 23 for twodifferent positions 26, 27 in which the pointing component 23 isdirected towards the current phenomenon 22, the position of the currentphenomenon 22 may be calculated. Alternatively, in combination with theposition- and orientation determination performed by means of thetransducer 5, other information may be used, such as one or more modelsof the environment. By using a model of the environment, in some cases,the position of the current phenomenon 22 may be determined by directingthe pointing component 23 including the transducer 5 towards thephenomenon 22 from one position only.

[0105] The locating member 4 could also include a sensor to obtaininformation from the environment by recording or measuring one or moreproperties of the environment in one or more positions and/or directionsat the same time as the position- and/or orientation determination isperformed. With such a device, other phenomena including such which arenot possible to indicate visually, may be located. For example, aradiation detector arranged in the pointing component would enabledetecting and locating of a radioactive leakage. It is also possible toprovide the locating member with a camera, such as a video camera, byarranging the camera on for example the pointing component, or onanother suitable position, for example by that the creature quite simplycarries the camera, with the purpose of obtaining further information bypicture recording of the environment in connection to the position-and/or orientation determination.

[0106] With reference to FIG. 9 the invention is described in connectionwith the application of determining the position and/or orientation ofan object 30 relative to an environment by means of a creature 3. Themethod comprises that the creature 3, for example a guard or a serviceperson, is connected to a locating member 4 including a transducer 5,that the locating member 4 is put by the creature 3 into mechanicalcontact with the object 30, that the position and/or orientation of thelocating member 4 relative to the environment is determined by means ofthe transducer 5 by receiving incident signals from signal sources 9 inthe environment, and that the position and/or orientation of the object30 is determined by means of the determined position and/or orientationof the locating member 4. In FIG. 9 a pipe 29 containing a flowingmedium is illustrated. The pipe 29 is provided with a flow measurementequipment 31 and a valve 32 for regulating the flow of the medium. Thevalve 32 may be adjusted by means of a handle 30 and thereby the flowmay be regulated. Thus, for different settings of the handle, differentflows in the pipe are obtained. In this connection the invention hasseveral applications. However, first of all, it should be emphasisedthat the embodiment illustrated in FIG. 9 is to be regarded only as anexample and although the invention is illustrated by means of the valve32 mentioned above, the invention may be applied in a similar waytogether with an arbitrary object 30. In this example, the handle 30 isdesigned for receiving one part of the locating member 4 including thetransducer 5. The transducer 5 is connected to a creature 3, suitably ahuman being, for example by the fact that the person 3 holds a part ofthe locating member 4 in the hand.

[0107] Preferably, the locating member 4 and the reference object, i.e.the handle 30, are designed to engage each other for fixing the locatingmember 4 and thereby the transducer 5 relative to the object 30. Thismay be performed by that a wedge-shaped pin 41 is introduced into acorresponding wedge-shaped grove 42. In this way it is possible todetermine, calibrate and/or adjust the position and/or orientation ofthe handle 30. For example, the service person 3 may determine that thehandle 30 is present in the desired position and/or transfer informationabout the position and/or orientation of the handle 30 to the (central)computer unit 11, 13 by applying the locating member 4 at the handle 30.The information may be used to check the state of for example atechnical process of any kind. Furthermore, it is possible to evaluate atechnical function by study how this function is effected by differentsettings of the current object. In the example, the valve 32 could forexample be calibrated by performing direct flow measurements by means ofthe flow measurement equipment 31 for different settings of the handle30, which settings are determined by means of the position- and/ororientation information produced by means of the transducer 5.

[0108] Another application of the invention is searching and mapping anobject, an area or a volume. In FIG. 10, an area 33 is schematicallyillustrated, which area may be for example a industrial estate close toa harbour, which is desired to be searched to investigate if drugs arepresent in the area. In this case, the creature 3 is suitably aneducated sniffer dog 3 which is connected to the transducer 5 by meansof a band 8 around the neck or the abdomen. Preferably, the locatingmember 4 also comprises a computer unit 11 and/or a locating member 4 isconnected to a central computer unit. The transducer 5, such aspreviously described determines continuously its position and/ororientation by receiving incident signals from signal sources 9 in theenvironment, and by means of the position and/or orientation determinedfor the transducer 5 the position and/or orientation of the dog 3 may bedetermined. This makes it possible to map the movement of the creature 3relative to the environment. Furthermore, it may be recorded at whichmoment the dog 3 has/had a certain position and/or orientation.

[0109] When the creature 3 moves relative to the environment, one ormore properties of the environment may be recorded and mapped. In thiscase, it is possible to record if drugs are present at this location ornot. The recording may be effected on the basis of the behaviour of thedog 3. For example, if the dog 3 moves in a normal way, probably thereare no drugs, whereas if the dog 3 is found to move and/or to make amotion in a particular way at a certain location, drugs may be present.The dog 3 could also bark when the dog has found something special andby means of a microphone included in the locating member 4 and the othercommunication means already described, the barking of the dog could betransferred to the (central) computer unit 11. Certainly, theinformation could also be transferred in a opposite direction in theform of commands to the dog 3. The creature 3 may move in anon-predictable way while the position and/or orientation of thecreature is determined continuously. However, it is also possible totrain the dog 3 to move, or to make a motion, in a trained way and inthat connection, the invention may be used such as described above, andto train the dog 3 to perform a certain motion and/or movement.

[0110] Another application in this connection is to document forresearch purposes how different animals move in different contexts. Forexample, a horse could be provided with one or more transducers arrangedon the legs of the horse for mapping the movement pattern thereof.

[0111] In the embodiment example regarding the sniffer dog 3, the methodmay be performed with or without a person leading the dog. Dispensingwith persons who lead the dog results in important reduction in costs.Furthermore, of course there are similar applications, such as searchingfor bombs in buildings.

[0112] Another application is directly or indirectly removal of mines bysecuring and recording mine-free areas. In areas where it occurs mines,particularly anti-personal mines, the invention may be used by thatcreatures are provided with locating members. The positions relative tothe environment which positions human beings or animals provided withlocating members have been present in, may be recorded while thesepeople, cattles, etc., are moving in a normal way in the environment,i.e. in the same way as they should have done also in absence of thelocating members. Hereby, mine-free positions may be recorded in aneffective way for creating information about mine-free areas andtrafficable roads. Certainly, it is also possible to more systematicinvestigate if mines are present in an area, for example by letting oneor more dogs repeatedly enter upon the area where mines are thought tobe present until sufficient position information is obtained to considerthat the area is cleared from mines.

[0113] In FIG. 11 a locating member 4 including a connection means 8 inthe shape of a bracelet arranged on an arm 34, to be used as anelectronic tag, is illustrated. The locating member 4 is in connectionwith an alarm unit 35, which suitably may be included in the bracelet,for transferring signals between the locating member 4 and the alarmunit 35. However, the alarm unit 35 could be separately arranged in anarbitrary position in the environment. The alarm unit 35 is suitablyarranged to emit a sound signal and/or signals to a (central) computerunit under certain conditions. These conditions may be for example thatthe transducer 5 has determined that the person 3 who carries thebracelet is present in a forbidden position and/or orientation, that thetransducer 5 is not switched on, that the transducer 5 does not work asintended, that the connection between the locating member 4 and thealarm unit 35 is broken or that the alarm unit 35 has been removed fromits intended position. Preferably, the alarm unit 35 is designed so thata special tool has to be used for removing the alarm unit from itsposition for example at the bracelet, so that such a removal performedwithout damaging the alarm unit 35, or another part of the device, maybe performed only by a certificated person having access to said tool.

[0114] By connecting the person 3 to the locating member 4 andestablishing a connection for communication between the locating memberand the alarm unit 35, an efficient so called electronic tag with uniquecharacteristics is obtained. From the locating member 4, informationabout the position and/or orientation of the person 3 may be transferredcontinuously, if so is desired, to an external supervision central, butthis is not in any way necessary for carrying out the supervision.Transferring of position- and/or orientation information to asupervision central may be performed at optional occasions, such as incase of an alert, an error function or if manipulation occurs, or anytransmission at all has to take place. Thus, another great advantage ofthe invention is that it enables supervision without the need oftransmitting signals from the locating member 4 to a receiver in theenvironment. The device according to the invention requires only thatsignals are transferred from the environment to the locating member 4,which signals do not contain any information about where the creature 3is present, and hereby the carrier of the electronic tag is protectedagainst non-certified bugging and tracking. This means that the riskthat people who are a threat against the safety of the person 3 are ableto track the person by bugging is considerably reduced or totallyeliminated.

[0115] Furthermore, it should be mentioned that all transferring ofsignals described in this application, particularly between the creature3 and the (central) computer unit 11, 13, certainly, may be coded and/orcompressed by means of existing technique to prevent non-certifiedbugging and for attaining high speed transmission, respectively.

What is claimed:
 1. A method for determining the position and/ororientation of a creature (3) relative to an environment, characterizedin that it comprises that the creature is connected to a locating member(4) including a transducer (5) so that the relative positions and/ororientations of the creature and the transducer are arranged to bewithin a limited interval, said transducer determining its positionand/or orientation relative to the environment by receiving incidentoptical signals from signal sources (9) in the environment and byrecording the relative incident positions of the received signals on asurface of the transducer, and that the position and/or orientation ofthe creature is determined by means of the position and/or orientationdetermined for the transducer.
 2. A method for determining the positionand/or orientation of a creature (3) relative to an environment,characterized in that it comprises that the creature is connected to alocating member (4) including a transducer (5) so that the relativepositions and/or orientations of the creature and the transducer arearranged to be within a limited interval, said transducer determiningits position and/or orientation relative to the environment by receivingincident signals from signal sources (9) in the environment by means ofat least one phased-array, and that the position and/or orientation ofthe creature is determined by means of the position and/or orientationdetermined for the transducer.
 3. A method according to claim 2,characterized in that for said signals microwaves are used.
 4. A methodaccording to claim 2, characterized in that for said surface acousticwaves are used.
 5. A method according to claim 1, characterized in thatwhen the creature (3) moves the position and/or orientation of thecreature is repeatedly determined by that the transducer (5) repeatedlydetermines its position and/or orientation by receiving incident signalsfrom signal sources (9) in the environment.
 6. A method according toclaim 1, characterized in that the position and/or orientation of thecreature (3) relative to its preceding position and/or orientation isdetermined.
 7. A method according to claim 1, characterized in that thepositions and/or orientations determined for the creature (3) arerecorded for mapping the movement of the creature relative to theenvironment.
 8. A method according to claim 6, characterized in that thepositions and/or orientations determined for the creature (3) arerecorded for mapping the relative movement of the creature.
 9. A methodaccording to claim 1, characterized in that when the creature (3) movesrelative to the environment at least one property of the environment isrecorded and/or mapped.
 10. A method according to claim 1, characterizedin that said determining of position and/or orientation of the creature(3) is performed while the creature moves in a non-predictable way. 11.A method according to claim 1, characterized in that said determining ofposition and/or orientation of the creature (3) is performed while thecreature moves in a trained way.
 12. A method according to claim 1,characterized in that when the creature (3) moves the movement of thecreature is directed by means of the position and/or orientationdetermined for the creature.
 13. A method for locating a phenomenon (22)in an environment, characterized in that it comprises that a creature(3) is connected to a locating member (4) including a transducer (5)mechanically connected to a component (23) intended for pointing outphenomena in the environment, that the pointing component is directed bythe creature towards the phenomenon from at least one pointing position,the transducer determining its position and/or orientation and therebydetermining the position and/or orientation of the pointing componentfor said at least one pointing position relative to the environment byreceiving incident signals from signal sources (9) in the environment,and that the position and/or orientation of the pointed out phenomenonrelative to the environment is determined by means of the positionand/or orientation determined for the pointing component.
 14. A methodaccording to claim 13, characterized in that the pointing component (23)is directed by the creature (3) towards the phenomenon (22) from twodifferent pointing positions.
 15. A method according to claim 13,characterized in that the position and/or orientation of the pointed outphenomenon is determined by means of a model (28) of the environment.16. A method for determining if the position and/or orientation of aphenomenon (22) relative to an environment is in accordance with areference, characterized in that it comprises that a creature (3) isconnected to a locating member (4) including a transducer (5) so thatthe relative positions and/or orientations of the creature and thetransducer are arranged to be within a limited interval, that thereference is defined by the introduction of at least one conditionregarding the position and/or orientation of the locating memberrelative to the environment, that the position and/or orientation of thelocating member relative to the environment is determined by means ofthe transducer by receiving incident signals from signal sources (9) inthe environment and by recording the relative incident directions of thesignals received by means of the transducer, and that the positionand/or orientation determined for the locating member is compared withthe reference so that at least one possibly occurring state in whichsaid at least one condition is fulfilled may be recorded.
 17. A methodaccording to claim 16, characterized in that the locating member (4) isput by the creature (3) into mechanical contact with an object (19, 30)in the environment for fixing the locating member or a part thereof andthereby the transducer (5) relative to the object so that said at leastone condition is fulfilled.
 18. A method according to claim 17,characterized in that the locating member (4) and the object (19, 30)are moved into engagement with each other so that said at least onecondition is fulfilled.
 19. A method according to claim 16,characterized in that states in which said at least one condition isfulfilled is recorded only when a further predefined measure isperformed substantially at the same time by the creature (3).
 20. Amethod for determining the position and/or orientation of an object (30)relative to an environment by means of a creature (3), characterized inthat it comprises that the creature is connected to a locating member(4) including a transducer (5), that the locating member is put intomechanical contact with the object by the creature, that the positionand/or orientation of the locating member relative to the environment isdetermined by means of the transducer by receiving incident signals fromsignal sources (9) in the environment and by recording the relativeincident directions of the signals received by means of the transducer,and that the position and/or orientation of the object is determined bymeans of the position and/or orientation determined for the locatingmember.
 21. A method according to claim 20, characterized in that theposition and/or orientation of the object (30) relative to its precedingposition and/or orientation is determined.
 22. A method according toclaim 20, characterized in that the locating member (4) and the object(30) are moved into engagement with each other for fixing their relativepositions and/or orientations.
 23. A method according to claim 1,characterized in that it comprises using of a signal receiving directionarea, that constitutes a solid angle exceeding 0.2 steradianes (sr), andwhich is formed by the collected amount of signal receiving directionsin which the transducer is arranged to receive incident signals fromsaid signal sources (9).
 24. A method according to claim 23,characterized in that the signal receiving direction area constitutes asolid angle that exceeds 1 steradian.
 25. A method according to claim23, characterized in that the signal receiving direction areaconstitutes a solid angle that exceeds 2 steradians.
 26. A methodaccording to claim 23, characterized in that the signal receivingdirection area constitutes a solid angle that exceeds 4 steradians. 27.A method according to claim 23, characterized in that it comprises usingof said signal receiving direction area which is topologicallyconnected.
 28. A method according to claim 1, characterized in thatoccurences caused by the presence of the creature (3) and/or the actionsthereof are recorded.
 29. A method according to claim 1, characterizedin that information is transferred from the locating member (4) to thecreature (3).
 30. A method according to claim 1, characterized in thatinformation is transferred from the creature (3) to the locating member(4).
 31. A method according to claim 29, characterized in thatinformation about the viewing direction of the creature (3) istransferred.
 32. A method according to claim 29, characterized in thatinformation about the movement direction of the creature (3) istransferred.
 33. A method according to claim 29, characterized in thatinformation about the nature of the environment is transferred.
 34. Amethod according to claim 29, characterized in that information aboutmovement paths (16) is transferred.
 35. A method according to claim 1,characterized in that information from the locating member (4) istransferred to at least one central computer unit (13).
 36. A methodaccording to claim 1, characterized in that information from at leastone central computer unit (13) is transferred to the locating member(4).
 37. A method according to claim 1, characterized in thatinformation from the transducer (5) is transferred to at least onecomputer unit (13) of the locating member (4).
 38. A method according toclaim 1, characterized in that information from at least one computerunit (11) of the locating member (4) is transferred to the transducer(5).
 39. A method according to claim 35, characterized in thatinformation is transferred to the creature (3) through a means arrangedin the environment and controlled by said computer unit (11, 13).
 40. Amethod according to claim 39, characterized in that information fromsaid information transferring means in the environment is transferred tothe creature (3) through a representation unit (15) of the locatingmember (4).
 41. A method according to claim 1, characterized in that thenature of the environment is recorded by the creature (3) by means of asensor.
 42. A method according to claim 1, characterized in that theposition and/or orientation of the transducer (5) is determined byrecording the relative incident directions of the signals received bymeans of the transducer.
 43. A method according to claim 2,characterized in that the position and/or orientation of the transducer(5) is determined by receiving incident optical signals from the signalsources (9) in the environment.